Luminaires using high intensity discharge (HID) light sources are commonly employed for commercial applications in retail and light industrial environments. The light provided by such luminaires is often accompanied by a level of glare which may be unacceptable to persons operating and functioning in these environments. Further, these luminaires may often provide more broadly distributed, upward directed light than is necessary or practical for certain commercial or work area applications.
The prior art has attempted to resolve the glare control issue for luminaires with HID lighting sources. One such reference is U.S. Pat. No. 4,858,091 (the '091 patent) issued to Herbert A. Fouke, who is also the inventor of the present invention. However, the '091 patent discloses an HID refractor luminaire which provides glare control in association with uptight control. Further, as shown in the candlepower distribution chart of FIG. 3 of the '091 patent, the luminaire of the reference also has a relatively broad light distribution, meaning it sends a greater deal of light above horizontal. Thus, there is less efficient use of luminaire to achieve a desired higher level of illumination. Accordingly, luminaires are spaced farther apart so there is no overlap.
Consequently, there is a need for an improved HID luminaire having relatively less uptight (less light above horizontal), higher levels of horizontal footcandle illumination, a more narrow (concentrated) light distribution, and further having improved glare control properties.